U.S. patent number 7,671,499 [Application Number 11/802,026] was granted by the patent office on 2010-03-02 for fan, motor and bearing structure thereof.
This patent grant is currently assigned to Delta Electronics, Inc.. Invention is credited to Hung-Chi Chen, Te-Tsai Chuang, Chung-Kai Lan.
United States Patent |
7,671,499 |
Lan , et al. |
March 2, 2010 |
Fan, motor and bearing structure thereof
Abstract
A bearing structure, which is cooperated with a shaft, includes
a housing, a bearing, an elastic element and a blocking element.
The shaft passes through the bearing. The elastic element presses
against the bearing to provide a pre-stress to the bearing. The
blocking element is apart from the bearing by a predetermined
distance.
Inventors: |
Lan; Chung-Kai (Taoyuan Hsien,
TW), Chen; Hung-Chi (Taoyuan Hsien, TW),
Chuang; Te-Tsai (Taoyuan Hsien, TW) |
Assignee: |
Delta Electronics, Inc.
(Taoyuan Hsien, TW)
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Family
ID: |
38748858 |
Appl.
No.: |
11/802,026 |
Filed: |
May 18, 2007 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20070273229 A1 |
Nov 29, 2007 |
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Foreign Application Priority Data
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May 26, 2006 [TW] |
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95118730 A |
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Current U.S.
Class: |
310/90 |
Current CPC
Class: |
H02K
5/1732 (20130101); H02K 5/1735 (20130101); F04D
25/062 (20130101) |
Current International
Class: |
H02K
5/16 (20060101) |
Field of
Search: |
;310/90,58,67R
;415/211.2,220 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nasri; Javaid
Attorney, Agent or Firm: Birch, Stewart, Kolasch &
Birch, LLP
Claims
What is claimed is:
1. A bearing structure cooperating with a shaft, the bearing
structure comprising: a housing; a bearing disposed inside the
housing, wherein the shaft passes through the bearing; an elastic
element disposed inside the housing and urging against the bearing
for providing a pre-stress to the bearing; and a blocking element,
wherein one end of the blocking element extends toward the bearing,
and another end of the blocking element is connected to the housing
so that a recess is formed between the blocking element and the
housing for accommodating the elastic element, wherein the blocking
element is separated from the bearing by a predetermined distance,
wherein the blocking element urges against an inner ring of the
bearing when the shaft rotates and moves in an axial direction
thereof.
2. The bearing structure of claim 1, wherein the blocking element
and the housing are integrally formed as a single piece.
3. The bearing structure of claim 1, wherein the elastic element is
a spring or a telescopic sleeve.
4. The bearing structure of claim 1, wherein the bearing is a ball
bearing.
5. The bearing structure of claim 1, further comprising a
positioning structure for positioning the bearing.
6. The bearing structure of claim 5, wherein the positioning
structure is a positioning plate, a positioning element or a
cylinder telescoped onto the shaft, or the positioning structure is
a protruding part or a turning part of the shaft.
7. The bearing structure of claim 1, wherein the housing comprises
a first housing and a second housing, and the blocking element
abuts on the bearing and is connected to one end of the first
housing.
8. The bearing structure of claim 7, wherein the blocking element
and the first housing are integrally formed as a single piece by
die casting or injection molding.
9. A motor comprising: a rotor structure having a shaft; a stator
structure disposed corresponding to the rotor structure; and a
bearing structure comprising: a housing; a bearing disposed inside
the housing, wherein the shaft passes through the bearing; an
elastic element disposed inside the housing and urging against the
bearing for providing a pre-stress to the bearing; and a blocking
element, wherein one end of the blocking element extends toward the
bearing, and another end of the blocking element is connected to
the housing so that a recess is formed between the blocking element
and the housing for accommodating the elastic element, wherein the
blocking element is separated from the bearing by a predetermined
distance, wherein the blocking element urges against an inner ring
of the bearing when the shaft rotates and moves in an axial
direction thereof.
10. The motor of claim 9, wherein the blocking element and the
housing are integrally formed as a single piece.
11. The motor of claim 9, wherein the elastic element is a spring
or a telescopic sleeve.
12. The motor of claim 9, wherein the bearing is a ball
bearing.
13. The motor of claim 9, further comprising a positioning
structure for positioning the bearing.
14. The motor of claim 13, wherein the positioning structure is a
positioning plate, a positioning element or a cylinder telescoped
onto the shaft, or the positioning structure is a protruding part
or a turning part of the shaft.
15. The motor of claim 9, wherein the housing comprises a first
housing and a second housing, and the blocking element abuts on the
bearing and is connected to one end of the first housing.
16. The motor of claim 15, wherein the blocking element and the
first housing are integrally formed as a single piece by die
casting or injection molding.
17. A fan comprising: an impeller having a hub and a plurality of
blades disposed around the hub; a rotor structure having a shaft
connected to the hub; a stator structure disposed corresponding to
the rotor structure; and a bearing structure comprising: a housing;
a bearing disposed inside the housing, wherein the shaft passes
through the bearing; an elastic element disposed inside the housing
and urging against the bearing for providing a pre-stress to the
bearing; and a blocking element, wherein one end of the blocking
element extends toward the bearing, and another end of the blocking
element is connected to the housing so that a recess is formed
between the blocking element and the housing for accommodating the
elastic element, wherein the blocking element is apart from the
bearing by a predetermined distance, wherein the blocking element
urges against an inner ring of the bearing when the shaft rotates
and moves in an axial direction thereof.
18. The fan of claim 17, wherein the elastic element is a spring or
a telescopic sleeve.
19. The fan of claim 17, further comprising a positioning structure
for positioning the bearing, wherein the positioning structure is a
positioning plate, a positioning element or a cylinder telescoped
on the shaft, or the positioning structure is a protruding part or
a turning part of the shaft.
20. The fan of claim 17, wherein the housing comprises a first
housing and a second housing, the blocking element abuts on the
bearing and is connected to one end of the first housing, and the
blocking element and the first housing are integrally formed as a
single piece by die casting or injection molding.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This Non-provisional application claims priority under 35 U.S.C.
.sctn.119(a) on Patent Application No(s). 095118730 filed in
Taiwan, Republic of China on May 26, 2006, the entire contents of
which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to a fan, a motor and a bearing structure
thereof. In particular, the invention relates to a fan, a motor and
its bearing structure that provides a pre-stress to the
bearing.
2. Related Art
In the modem information era, electronic equipment has become an
indispensable part of daily life and work. Motors in particular are
widely used in various electronic devices to effectively convert
electrical energy into mechanical energy.
There are many types of motors. FIG. 1 shows a conventional
brushless motor 1. The brushless motor 1 includes a housing 10, a
rotor structure 11 and a stator structure 12. The rotor structure
11 has a shaft 111 passing through the housing 10. The stator
structure 12 has a coil set 121, which fits around with the housing
10. An annular magnet 112 of the rotor structure 11 is disposed
corresponding to the coil set 121. The interaction between the coil
set 121 and the magnet 112 generate an alternated magnetic field to
rotate the rotor structure 11.
To make the motor 1 operate smoothly, a bearing 13 is generally
used to cover the shaft 111. Consequently, the shaft 111 rotates
well with the support of the bearing 13. As well, the bearings 13
can be classified into ball bearings, sleeve bearings and sliding
bearings according to the structures thereof. Take the ball bearing
as an example that has an inner ring 131, an outer ring 132 and a
ball 133. The inner ring 131 is mounted on the shaft 111. The outer
ring 132 is connected to the housing 10. The ball 133 is disposed
between the inner ring 131 and the outer ring 132. In order to make
the shaft 111 run more smoothly with the support of the bearing 13,
the motor 1 further includes an elastic element 14 disposed between
the bearing 13 and a cover 15. As shown in FIG. 1, the elastic
element 14 presses against the inner ring 131 of the bearing 13 to
provide a pre-stress to the bearing 13 so as to make the ball 133
of the bearing 13 maintains linear contact with the inner ring 131
and the outer ring 132 simultaneously. This mechanism buffers the
axial load variation to the bearing 13 under the high-speed
rotation of the shaft 111, thereby elongating the lifetime of the
motor 1. According to the different configurations, the elastic
element 14 can press against the outer ring 132 of the bearing 13
as well that provides pre-stress on the bearing 13 as shown in FIG.
2.
However, a spring is used as the elastic element 14 generally.
After a long-time use of the motor 1, the continuous pressure
imposed on the bearing 13 is easy to cause elastic fatigue for the
elastic element 14. This seriously shortens the lifetime of use of
the motor 1.
Therefore, it is an important subject to provide a fan, a motor and
a bearing structure thereof that can provide a pre-stress to the
bearing and prevent the elastic element from being overly
pre-stressed and damaged.
SUMMARY OF THE INVENTION
In view of the foregoing, the invention is to provide a fan, a
motor and a bearing structure thereof that can provide a pre-stress
to the bearing and prevent the elastic element from being overly
pre-stressed and damaged.
To achieve the above, the invention discloses a bearing structure,
which cooperates with a shaft and is disposed in a housing. The
bearing structure includes a bearing, an elastic element and a
blocking element. The shaft passes through the bearing, and the
elastic element presses against the bearing to provide a pre-stress
to the bearing. The blocking element is separated from the bearing
by a predetermined distance.
To achieve the above, the invention discloses a motor, which
includes a housing, a rotor structure, a stator structure and a
bearing structure. The rotor structure has a shaft passing through
the housing. The stator structure is disposed corresponding to the
rotor structure and is fit with the housing. The bearing structure,
which cooperates with the shaft and is disposed in the housing. The
bearing structure includes a bearing, an elastic element and a
blocking element. The shaft passes through the bearing, and the
elastic element presses against the bearing to provide a pre-stress
to the bearing. The blocking element is separated from the bearing
by a predetermined distance.
To achieve the above, the invention discloses a fan, which includes
an impeller, a housing, a rotor structure, a stator structure and a
bearing structure. The impeller includes a hub and a plurality of
blades disposed around the hub. The rotor structure has a shaft,
which passes through the housing and connects to the hub. The
stator structure is disposed corresponding to the rotor structure
and is fit with the housing. The bearing structure, which
cooperates with the shaft and is disposed in the housing. The
bearing structure includes a bearing, an elastic element and a
blocking element. The shaft passes through the bearing, and the
elastic element presses against the bearing to provide a pre-stress
to the bearing. The blocking element is separated from the bearing
by a predetermined distance.
As mentioned above, the invention discloses a fan, a motor and a
bearing structure thereof. The blocking element is separated from
the bearing by a distance. The elastic element presses against the
bearing. The blocking element has a recess for accommodating the
elastic element. Therefore, if the shaft of the motor or fan
rotates at a high-speeded rotation and moves toward an axial
direction, the elastic element provides a pre-stress to the
bearing. The blocking element is used to prevent from doing
excessively the pre-stress on the elastic element if the bearing is
impacted. This effectively prevents the elastic element, such as a
spring, from being damaged during the impact. Therefore, the
invention can provide a better protection for the bearing structure
and elongate the lifetime thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will become more fully understood from the detailed
description given herein below illustration only, and thus is not
limitative of the present invention, and wherein:
FIG. 1 is a sectional view of a conventional brushless motor;
FIG. 2 is a sectional view of a conventional bearing with a
pre-stress structure;
FIGS. 3 and 4 are sectional views of a bearing structure according
to a preferred embodiment of the invention;
FIG. 5 is a sectional view of a motor according to the preferred
embodiment of the invention;
FIG. 6 is a sectional view of a motor according to another
embodiment; and
FIG. 7 is a sectional view of a fan according to the preferred
embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be apparent from the following detailed
description, which proceeds with reference to the accompanying
drawings, wherein the same references relate to the same
elements.
As shown in FIG. 3, a bearing structure 20 according to a preferred
embodiment of the invention includes a bearing 21, an elastic
element 22 and a blocking element 23. The bearing structure 20 is
cooperated with a shaft and is disposed in a housing 25. The
housing 25 consists of a first housing 251 and a second housing
252.
The shaft 24 passes through the bearing 21. In this embodiment, the
bearing 21, such as a ball bearing, includes an inner ring 211, an
outer ring 212 and a ball 213. The inner ring 211 is fit with the
shaft 24. The outer ring 212 is connected to the first housing 251.
The ball 213 is disposed between the inner ring 211 and the outer
ring 212.
The elastic element 22 presses against the bearing 21 to provide a
pre-stress to the bearing 21. In this embodiment, the elastic
element 22 is, for example, a spring or a flexible sleeve.
The blocking element 23 is disposed adjacent to the bearing 21 and
connected to one end of the first housing 251 or alternatively
integrated with the first housing 251. In this embodiment, the
blocking element 23 and the first housing 251 can be integrally
formed by die casting or injection molding. A recess 26 is formed
between the blocking element 23 and the first housing 251 to
accommodate the elastic element 22. One end of the blocking element
23 is separated from the bearing 21 by a predetermined distance G
If the shaft 24 rotates and moves toward an axial direction D, the
bearing 21 is pulled toward the elastic element 22 so as to depress
the elastic element 22. That is, the gap between the inner ring
211, the outer ring 212 and the ball 213 of the bearing 21 is
eliminated by the elastic restoring force produced from the elastic
element 22. The blocking element 23 is used to press against the
bearing 21, particularly to the inner ring 211, to prevent the
bearing 21 from doing excessively the pre-stress of the elastic
element 22. The elastic fatigue of elastic element 22, which
shortens the lifetime of the bearing 21, is thus avoided. The
blocking element 23 presses against the inner ring 211 of the
bearing 21 is only an example, and the invention is not limited to
this. According to the actual design, the blocking element 23 is
pressed against the outer ring 212 to achieve the purpose of
preventing from doing excessively the pre-stress on the elastic
element 22 as well.
The bearing structure 20 in this embodiment further includes a
positioning structure 27, disposed on the other side of the bearing
21 opposite to the pre-stress direction to press against and
position the bearing 21. As shown in FIG. 3, the positioning
structure 27 is a positioning element mounted on the shaft 24. The
positioning element is, for example, a positioning plate as shown
in FIG. 3. Alternatively, it can be a cylinder as shown in FIG. 4.
In addition, the positioning structure 27 can be a protrusion from
the shaft 24 or a turning part 252a of the second housing 252, not
shown in drawing.
As shown in FIG. 5, the motor 3 according to a preferred embodiment
of the invention includes a housing 30, a rotor structure 31, a
stator structure 32 and a bearing structure 33. In the embodiment,
the housing 30 is, for example, a bearing sleeve.
In this embodiment, the motor 3 is implemented as a brushless
motor. Of course, this is only one example of the invention, and
the invention s not limited to this. The motor 3 is a brush motor
or any type of motor as well.
The rotor structure 31 includes a cover 311, a shaft 312 and a
magnet 313. The shaft 312 connects to the cover 311. The magnet 313
is disposed around the inner sidewall of the cover 311. The rotor
structure 31 is disposed inside the housing 30, and the shaft 312
passes through the housing 30. Herein, the housing 30 can be a
bearing sleeve (as shown in FIG. 5). Besides, according to the
actual design of the motor, the housing 30 can be a base or a
housing of the motor 3 (not shown in drawing). The motor 3 is an
inner-rotor type motor.
The stator structure 32 includes a stator magnetic pole 321
disposed in the housing 30. The stator magnetic pole 321 is formed
by a coil set and disposed corresponding to the rotor structure 31,
particularly to the magnet 313. A circuit board 34 is disposed in
the housing 30 and electrically connected to the stator magnetic
pole 321 in order to control the current direction of the stator
magnetic pole 321. Therefore, a rotating magnetic field is
alternately produced to rotate the rotor structure 31.
The bearing structure 33 is disposed in the housing 30 and fits
with the shaft 312. In the embodiment, the bearing structure 33
includes a bearing 331, an elastic element 332 and a blocking
element 333.
Since the relative positions, structure features, constituent
materials and functions of the components in the bearing structure
33 of this embodiment are the same as those in the previous
embodiment, the descriptions are omitted herein.
In this embodiment, the motor 3 is implemented as a brushless
motor, a brush motor or other types of motor. As shown in FIG. 6,
the bearing structure of the invention can be used in an
inner-rotor type motor 5. The motor 5 includes a housing 50, a
rotor structure 51, a stator structure 52 and a bearing structure
53. The stator structure 52 includes a permanent magnet 521, and
the rotor structure 51 includes a shaft 511 and a silicon steel set
512. The shaft 511 passes through the housing 50, and the silicon
steel set 512 is fixed to the shaft 511. The silicon steel set 512
is wound with a coil and corresponded to the permanent magnet 521.
Because the primary driving structure of the inner-rotor type motor
5 is well-known in the prior art, the rotor structure 51 and the
stator structure are not further described herein.
The bearing structure 53 is disposed inside the housing 50 and
includes a bearing 531, an elastic element 532 and a blocking
element 533. Herein, the housing 50 is the outer case of the
inner-rotor type motor 5 and cooperates with the shaft 511.
Likewise, the relative positions, structure features, constituent
materials and functions of the components in the bearing structure
53 of this embodiment are the same as those in the previous
embodiments, the detailed descriptions are omitted.
As shown in FIG. 7, a fan 4 according to a preferred embodiment of
the invention includes an impeller 40, a housing 41, a rotor
structure 42, a stator structure 43 and a bearing structure 44.
Since the structure features, relative positions, constituent
materials and functions of the components in the housing 41, the
rotor structure 42, the stator structure 43 and the bearing
structure 44 are the same as those in the previous embodiments, the
detailed descriptions are omitted.
In this embodiment, the impeller 40 includes a hub 401 and several
blades 402. The blades 402 are disposed around the hub 401. As
shown in FIG. 7, the hub 401 is a cover 421 connected to the rotor
structure 42, and a shaft 422 is connected to the hub 401. When the
shaft 422 rotates, the blades 402 are driven to generate
airflow.
In summary, the invention discloses a fan, a motor and a bearing
structure thereof. The blocking element is separated from the
bearing by a distance. The elastic element presses against the
bearing. The blocking element has a recess for accommodating the
elastic element. Therefore, when the shaft of the motor or fan
rotates at a high speed and moves in an axial direction, the
elastic element provides a pre-stress to the bearing. The blocking
element is used to prevent the bearing from imposing excess
pre-stress on the elastic element under impact. This effectively
prevents the elastic element, such as a spring, from being damaged
during the impact. Therefore, the invention can provide better
protection for the bearing structure and lengthen the lifetime
thereof.
Although the invention has been described with reference to
specific embodiments, this description is not meant to be construed
in a limiting sense. Various modifications of the disclosed
embodiments, as well as alternative embodiments, will be apparent
to persons skilled in the art. It is, therefore, contemplated that
the appended claims will cover all modifications that fall within
the true scope of the invention.
* * * * *